This invention relates to improvements in slide projectors of the type which utilizes an adjustable lens unit to enlarge images on small slides which are located in the path of a light beam.
The object of the invention is the provision of means to manually or power focus the adjustable lens unit of the projector. The power adjustment can be made irrespective of the position of the adjustable lens unit and safety features are incorporated which prevent locking and possible damage to the adjustment means when the limit of adjustment of the lens unit in a given direction has been reached.